Heat exchanger fin tube



Oct. 2, 1945s. F. T; ELDER 2,386,159

HEAT EXCHANGER FiN-TUBE Filed Feb. 17, 1944 INVENTOR Freder/ckTEldel" BY I aiented Get. 2, 19%5 @NETEE STAT asserts as serene assess i asser s HEAT E'XCHANGER FIN TUBE Frederick '1'. Elder, Mountain Lakes, N. a, assignor to American Locomotive Company, New York, N. Y a corporation of New York application February 17, 1944, Serial No. 522.702

2 Claims.

embodiment thereof.

Referring to the drawing forming a part of this application, Figure-l is a section on the line I-I of Fig. 2, showing the fin-tube of the present invention, parts being shown in full; Fig. 2 is a section on the line 11-41 of Fig. 1; Fig. 3 is a section on the line III-III of Fig. 1; Fig. 4 is a. plan of a metal blank employed in forming the fins of the tube; and Fig. is an isometric view of a portion of the fin-providing sheet metal structure ready for insertion into the tubular member.

A fin-tube'embodying the present invention is shown in the drawing and is designated by the reference numeral I, For convenience a short tube is shown, but it may, of course, be of any desired length. It includes a tubular member 2 in which is disposed a fin-providing hollow metal structure 3 securely bonded to the inner face of the tubular member 2 as by soldering or welding.

The structure 3 is shown formed of a single sheet of metal, perforated and bent in a suitable manner to provide longitudinal rows of discontinuousfins. The structure 3 is of cylindrical internally corrugated form. It is contemplated that in a tube of large diameter, the structure 3 might be made up of several pieces disposed side by side, or in a tube of great length the structure 3 might be made up of several pieces disposed end to end.

In forming the structure 3, a flat piece or sheet metal 4 is chosen of suitable length and width for the tubular member with which it is to be employed. A plurality of longitudinal rows of elongated perforations 5 are formed in the sheet. The longitudinal edges of the sheet shown in Fig. 4 are designated by the numeral 8 and the transverse edges by the numeral I. The perforations shown are diamond-shaped, but may be shaped in other suitable forms if desired.

After the perforations are formed the sheet is bent'or arched through the longitudinal center (dot-dash lines) of each of the rows of perforations 5 to an angle equal to the angle a shown in tween the rows of perforations and adjacent the edges 6 are then curved to form of sheet 5 the aforesaid cylindrical corrugated structure, the

outside diameter of which will be equal to the inside diameter of the tubular member 2 in which the structure is to be disposed. The perforations are elongated in a transverse direction and the defining edges of each perforation diverge from the ends of the major axis of the perforation to the ends of the minor axis thereof.

The curved portions between the rows of perforations of the structure 3 form three longitudinal base portions 8 in the middle of one of which there will be a seam formed by the meeting of the edges 6. The portions between the perforations of each row and outwardly beyond the end perforations of each row to edges 1 form a plurality of short double-walled fins 9. Each fin 9 has two side walls in, converging toward the axis of the tubular member, each of which provides a short stripfin type fin surface. The side walls ID, at their edges opposite their apex, are integral with the adjacent base portions. As the perforations are diamond-shaped, each side wall ii! is keystone-shaped.

While three longitudinal rows of fins 9 have been shown in the drawing, it will be obvious that a greater or lesserv number may be provided, if

desired. The base portions 8 provide ample sur- I 'turbulence increasing the heat exchange rate.

While the perforations 5 are shown in the drawing also arranged in transverse rows, they may be staggered if desired.

While there has been hereinbefore described an approved embodiment of the invention, it will be understood that many and various changes and modifications in form, arrangement of parts and details of construction thereof, may be made without departing from the spirit ofthe invention and that all such changes and modifications as fall within the scope of the appended claims are contemplated as a part of this invention.

The invention claimed and desired to be secured by Letters Patent is:

1. A heat exchanger fin-tube comprising a Fig. 3. The longitudinal portions of sheet i be- '5 tubular member; and a hollow sheet metal structure within said member having circumi'erentialiy alternate base portions and inwardly projecting 1 V-shaped portions extending longitudinally of said member, said base portions eng gin and being bonded to the inner face or said member and each of said V-shaped portions having a longitudinal row 01' spaced orifices, each of said orifices extending from one of the adjacent base portions through the apex of its V-shaped portion to the other adjacent base portion, said orifices providing of each of said V-shaped portions a longitudinal row or V-shaped double-walled fins.

2. A heat exchanger fin-tube comprising a tubular member; and a hollow sheet metal structure within said member having circumterentially FREDERICK T. ELDER. 

